MESURA 2000: a strategy to integrate a true communication network of metrology experts with process technology experts

 The Centro Nacional de Metrología (CENAM) has developed the MESURA Interinstitutional Network in collaboration with other research and development institutes in Mexico. This network has the aim of providing integral metrological services to industry throughout the country, with uniform standards of quality and consistency. The fulfillment of this aim has been possible because of a number of factors that have made the MESURA Program an attractor for the integration of metrological services. Among these factors are: an unswerving focus on the customer needs, an integral and logical problem solving approach to consultancy, adequate modular classification of the consultants functions, clear-cut definition of the functions of each member of interdisciplinary groups, and a uniform code of communication among the members of the network. The next stage of the strategy is to strengthen the link between metrology and its industrial applications forming a new type of consultant with the technical experts from R&D Centers. These will be consultants with general knowledge and experience in metrology, specialized in certain type of industrial processes and products. The strategy will be initiated in the year 2000 and with it the MESURA Network is expected to make a strong contribution to fostering the optimum use of metrology in industry and to act as a channel for the integration of other technologies in which the participating Centers have expertise.     

A Practical Enantioselective Synthesis of (-)-NS-49 #

Asymmetric synthesis of (-)-NS-49 (1) was achieved by a convenient and short route.

     

Ion–laser interactions: The most complete solution

Trapped ions are considered one of the best candidates to perform quantum information processing. By interacting them with laser beams they are, somehow, easy to manipulate, which makes them an excellent choice for the production of nonclassical states of their vibrational motion, the reconstruction of quasiprobability distribution functions, the production of quantum gates, etc. However, most of these effects have been produced in the so-called low intensity regime, this is, when the Rabi frequency (laser intensity) is much smaller than the trap frequency. Because of the possibility to produce faster quantum gates in other regimes it is of importance to study this system in a more complete manner, which is the motivation for this contribution. We start by studying the way ions are trapped in Paul traps and review the basic mechanisms of trapping. Then we show how the problem may be completely solved for trapping states; i.e., we find (exact) eigenstates of the full Hamiltonian. We show how, in the low intensity regime, Jaynes–Cummings and anti-Jaynes–Cummings interactions may be obtained, without using the rotating wave approximation and analyze the medium and high intensity regimes where dispersive Hamiltonians are produced. The traditional approach (low intensity regime) is also studied and used for the generation of non-classical states of the vibrational wavefunction. In particular, we show how to add and subtract vibrational quanta to an initial state, how to produce specific superpositions of number states and how to generate NOON states for the two-dimensional vibration of the ion. It is also shown how squeezing may be measured. The time dependent problem is studied by using Lewis–Ermakov methods. We give a solution to the problem when the time dependence of the trap is considered and also analyze a specific (artificial) time dependence that produces squeezing of the initial vibrational wave function. A way to mimic the ion–laser interaction via classical optics is also introduced.     

Spin relaxation in nanowires by hyperfine coupling

Hyperfine interactions establish limits on spin dynamics and relaxation rates in ensembles of semiconductor quantum dots. It is the confinement of electrons which determines nonzero hyperfine coupling and leads to the spin relaxation. As a result, in nanowires one would expect the vanishing of this effect due to extended electron states. However, even for relatively clean wires, disorder plays a crucial role and makes electron localization sufficient to cause spin relaxation on the time scale of the order of 10 ns. (© 2012 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)     

Priestley dualities for some lattice-ordered algebraic structures, including MTL, IMTL and MV-algebras

In this work we give a duality for many classes of lattice ordered algebras, as Integral Commutative Distributive Residuated Lattices MTL-algebras, IMTL-algebras and MV-algebras (see page 604). These dualities are obtained by restricting the duality given by the second author for DLFI-algebras by means of Priestley spaces with ternary relations (see [2]). We translate the equations that define some known subvarieties of DLFI-algebras to relational conditions in the associated DLFI-space. The authors are supported by the Agentinian Consejo de Investigaciones Cientificas y Tecnicas (CONICET).     

Curing kinetics of amine and sodium hydroxide catalyzed phenol-formaldehyde resins

The effect of both formaldehyde content and catalyst type used in the synthesis of several resole type phenolic resins has been studied by using differential scanning calorimetry. In this study Kissinger-Akahira-Sunose (KAS), Ozawa-Flynn-Wall (OFW) and Friedman model-free kinetics are applied in order to correlate the dynamic cure behaviour with the mentioned synthesis variables. Strong upward dependency of activation energy on conversion has been detected in all cases up to a maximum value. Lower the formaldehyde content fewer changes in activation energy have been detected, revealing a more homogeneous polymerization. As formaldehyde content increases, stronger variations of energy values have been observed and the maximum value is shifted to lower conversions. By comparing triethylamine and sodium hydroxide catalysts similar behaviour has been observed, with higher energy values and shifting of the maximum in the latter. Friedman approach has been resulted in more convenient and accurate for the energy values determination and KAS method seems useful for the dynamic cure prediction of that type of thermoset.     

catena‐Poly[[[tetrakis(1‐methylimidazole‐κN3)copper(II)]‐μ2‐sulfato‐κ2O:O′] acetonitrile hemisolvate sesquihydrate]

The title compound, [Cu(C₄H₈N₂)₄]SO₄·0.5CH₃CN·1.5H₂O, consists of a double chain wherein the Cu centres are octahedrally coordinated by four 1‐methyl­imidazole ligands in the equatorial plane and by two axial sulfate ions which act as bridges between the Cu centres. The Cu—N bond lengths lie between 1.9929 (14) and 2.0226 (14) Å, but the Cu—O bond distances are longer, with values between 2.3496 (13) and 2.8276 (14) Å. The water mol­ecules participate in the formation of a network of hydrogen bonds of significance in maintaining the connectivity of the structure.